Toto Eco supreme flush problem

I installed a new Eco supreme (round) and I am having a problem with the flush. About every fifth flush doesn't clear the bowl (no siphoning). I am using a regular wax ring (no horn) and dont think the outlet is blocked. The bowl seems underfilled because the water spot is smaller than spec. I checked the filter in the fill valve but it was clean. Would being underfilled cause a poor flush? Any thoughts?

Yep. Open the tank. Look at the water level. A description of the proper water level is stamped in the tank, usually 1/2" or 1/4" below the top of the overflow riser. I'm guessing you are not getting enough refill water because the refill cycle isn't going on long enough. Adjust the water level to the proper level (or a smidge more if you want) and see how that works. Instructions for adjusting the water level depend on the type of fill valve used.

Also, make sure that the refill hose is directed into the overflow riser and daylighted above it on a clip. If it isn't, then you are getting NO refill water. The refill hose is connected to the fill valve, and, as I say, should run over to and dump into the overflow riser.

Here's what the process should look like:

If you have the valve with the white screw on it, turn the screw to adjust the water level. If you have one without the screw, like the one in the video, let me know and I will give you the instructions.

Let us know whether this works. If it doesn't, there are other potential problems but this one is the most likely.
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Thanks for the reply. I forgot to mention that I already checked and adjusted the level in the tank (white screw). It is supposed to be 1/2" below overflow and that is where it is. The water from the fill valve is spraying correctly into the overflow also.

After you have flushed and the refill is complete, does the water spot drain out? In other words, does it dribble down from the right size to too-small-a-size. That could be caused by a number of things, a supremely-unlevel toilet being one possibility. You can also try adjusting the water level to 1/4" and see if that helps.

So the tank is refilling to the right level, and whatever water runs into the bowl stays there, but the bowl isn't filling sufficiently, correct?

I would check the refill tube to make sure it isn't kinked or squished at either end. Step one is going to be getting a little more water in there. Impatient person that I am, I might just go to Lowes and get a Korky 528MP fill valve and swap it for the one in there; it has an adjustable refill percentage so you can set it as you like. It's basically-identical to the other valve that Toto uses.

Alternatively, I would call Toto customer service and discuss it with them. They will probably send you a new fill valve for free, assuming that you can be sure that this isn't a hose problem. Friendly folks in Georgia, USA: 1-888-295-8134

It's either the hose is narrowed somewhere or the fill valve isn't delivering the proper refill percentage. Like I said, you can kluge the issue by raising the water level in the tank a little, but swapping the fill valve is another possibility.

Longer-shot possibilities include that something is causing the flush to not finish and start bowl refill at the expected time, leading to a late start to the bowl actually refilling while the tank has been filling and water running through the riser is going down the bowl with the flush rather than being used to refill it. Some of that is expected, but too much and you don't get a full refill. However, on the gmax flush, it should take place so quickly, this shouldn't really be possible.

If you SLOWLY pour some water in the bowl, does the level rise and STAY there? If so, then somehow, the bowl is not being refilled properly. If it rises, then falls back to the original level, that isn't the issue.

I called Toto and they are sending me a new fill valve. It sounded like they were going to send the korky maxperformance because they said the replacement would be different and have adjustable refill ratio. So far I am unimpressed with this toilet. It hasn't clogged yet, but it doesn't clear the bowl too well (leaves bits of toilet paper behind) and seems to require multiple flushes. It's difficult for me to believe that this is so precisely engineered that a bit more water in the bowl will make a huge difference in the siphoning effect, but I am willing to try it before I return the product.

Unless the bowl is at the correct height, the siphon doesn't start.
An underfilled bowl requires the first potion of water from the tank to fill the bowl, which just gets it to it's prestart postition.

Older toilets overfilled the bowl by a few gallons in some cases.
New toilets try to prevent the wasteage.

I can tell you that with our Carlyle II, adjusting the water level so the bowl started off full made all the difference in the world.

They're sending you the TSU99A.X Universal Replacement Fill Valve. It's basically a Korky MaxPerformance 528MP with some bells and whistles to make sure you get the water level and flow rate exactly like it's supposed to be. That said, feel free to adjust the refill valve so that you get a full bowl to start.

Update on this for those wondering--I installed the tsu99a.x. The instructions aren't quite right for this tank/toilet model because the valve is too high (supposed to count the notches in the lower valve body) so the water level is right at the top edge of the overflow. Unfortunately I have to uninstall the valve to adjust the height and water level because there isn't enough space in the tank to pivot the fill valve adjustment mechanism.

Good news is that after a few test flushes the toilet seems to be working great with the bowl level set correctly. This has left me wondering if I had set the water level of the original e-max valve to the rim of the overflow, the bowl level might have been correct. I had it 1/2" below as instructed.

Unfortunately I have to uninstall the valve to adjust the height and water level because there isn't enough space in the tank to pivot the fill valve adjustment mechanism.

Click to expand...

When adjusting the height, I don't rotate the top of the valve. I loosen the nut a smidge, and hold the valve top in one hand while rotating the stem from under the tank until unlocked. Then I set the head at whatever height I want, then rotate the stem back again from underneath to lock. It's a nifty little trick that works pretty well. Then just tighten the nut back up and you're set.

Or put a bucket underneath or use a turkey baster. I often get away with just a small amount of water running out as I loosen the nut just enough to turn the stem. But some will come out, and sometimes more than other times.

Anyway, I'm glad that you are up and running. If you want to keep it a little on the high side, I don't see the harm. Of course, with the TSU99a.x, you can reduce the tank level a notch or two and open the refill a little more.

I reduced the height two notches and adjusted the refill a bit. Do you know if Toto has different flush valves for the one-piece e-max toilets? Maybe mine has one with a shorter overflow tube and that's why I needed to lower the fill valve.

Whether they use multiple manufacturers for the flush valves, I don't know. However, whomever they use should produce a flush valve that has an overflow riser of a certain height. It is interesting that when you set the TSU99A.X on the proper peg, it gave you a water height right at the top of the overflow riser, and it appeared that that water height was correct.

Glad you are back in business and that everything is now working properly! It's amazing, isn't it, how having a full bowl at the start of the flush makes such a big difference. When we tell people this, they find it hard to believe sometimes, but it is definitely the case.